Why is there a need to redirect?
Everybody has to delete posts or pages at some point, whether you’re cleaning up pages on your site or changing the site structure. Deleting comes with a risk though, because when the old URL gets visitors, they’ll be served a 404 not found error. Landing on a 404 error page is something you should avoid at all times, for both user friendliness and SEO ( search engine optimization ).
In most cases, especially for a frequently visited page, you’d want to redirect the old URL to a new one.
What is a redirect?
The name ‘redirect’ pretty much says it all: it sends visitors traveling to a specific page to an alternative one.
By setting up 301 redirects from your old pages to your new pages, any incoming links will be seemlessly passed along, and their pagerank will be passed along with them.
WordPress Plugin Resource
Simple 301 Redirects provides an easy method of redirecting requests to another page on your site or elsewhere on the web. It’s especially handy when you migrate a site to WordPress and can’t preserve your URL structure.